Key Engineering Materials Vol. 519

Abstract: In this study, nano ZrO₂ powders were incorporated into Al-5 wt% Zn sacrificial anode and the effect of ZrO₂ contents (wt% =0.1, 0.2) on microstructures and electrochemical properties were investigated. The results show that the addition of nano ZrO₂ was effective on improving metallurgical and electrochemical properties. With the increase of ZrO₂ content, the dendritic structure is fined gradually and the corrosion current density values is also increased. The incorporation of ZrO₂ also can result in a moderate efficiency value. When the ZrO₂ content in the alloy was 0.2 wt%, the optimal microstructure, electrochemical properties and as high as 70% the efficiency value was obtained.

Abstract: La_2/3Sr_1/3MnO₃: Ag_x (LSMO: Ag_x) polycrystalline composites were prepared by co-precipitation method. Structure and performance of La_2/3Sr_1/3MnO₃: Ag_x were investigated by X ray diffraction and R-T measurement. Results show that, all samples are perovskite structure. With the addition of Ag increased, the volume and conductivity of LSMnO: Ag_x were increased accordingly. The resistivity of the samples (x=0.30, 0.40) is only 10% of the pristine. The TCR of LSMO: Agx (x=0.3) is obtained maximum value of 3.39% as the Z value 0.50. It’s perhaps the proper candidate material to be high temperature electrode or near room temperature bolometer and infrared devices.

Abstract: A kind of conductive composite material for the bipolar plate of proton-exchange membrane fuel cells (PEMFC) was fabricated by the hot-pressure molding with graphite powders and polyphenylene sulfide (PPS) resin powders. The influencing factors including PPS resin content, molding pressure and molding temperature, and temperature holding time on the conductivity, flexural strength and density of the composite were investigated. It was found that the perfect conditions for the fabrication of bipolar plate were that the PPS resin content was 25%wt, the forming pressure was 20 MPa, the mold temperature was 320°C and the holding time was 25 min.

Abstract: Abstract:Mn salts[MnSO4]-doped TiO2 electrodes thin film was synthesized by the hydrothermal method. To prepare the working electrode, The TiO2 or Mn-doped TiO2 slurry was coated onto the fluorine-doped tin oxide glass substrate by the doctor blade method and was then sintered at 450 °C. X-ray photoelectron spectroscopy (XPS) data indicated that the doped Mn ions exist in forms of Mn7+. This study show a photovoltaic efficiency of 5.15%, which is higher than that of the undoped TiO2 thin film (4.14%) and increase photovoltage and fill factors by 13.2% from 455 mV to 515mV, 39.3% from 499 to 695 respectively.

Abstract: For physical structure of TiO₂ films is the core of photoelectric conversion on the photovoltaic performance of DSSC, the method by parameter estimate to determine the optimal thickness of DSSC working electrode is deduced, which is consistent with the analysis of real physical meaning about the TiO₂ layer thickness and the photocurrent, while gives the specific optimal value as an addition. As a mathematical proof of the optimal conclusion extracting from the complex working mechanism of DSSCs and accidental factors, the equivalent circuit parameters of each curve are estimated corresponds to the equivalent circuit method first. According to the inflection point, which obtained through the synthesis of scattered experment points to the trend curve, the optimal thickness of DSSC working electrode are optimal identified.

Abstract: The nest-like NiO was successfully prepared by calcining the Ni(OH)₂ precursor synthesized using wet chemical deposition method. A NiO-based p-type dye-sensitized solar cell was fabricated. The photocathode films were coated by doctor-blading NiO paste onto the FTO substrates. The thickness of NiO film was controlled by repeatedly blade coating using one layer of tape. The results manifested that the thickness of the NiO film significantly influenced the photoconversion efficiency. The solar cell based on the NiO film with 13 μm thickness showed the highest photoconversion efficiency. In addition, the influence of the dye is also investigated. The NiO films were sensitized with C343, N3, and Z907, respectively. The measurement of photocurrent density-voltage characteristics indicated that the highest photoconversion efficiency is about 0.027% using C343 sensitized.

Abstract: CuInS2 has been deposited onto the mesoporous TiO2 films by in sequence growth of InxS and CuyS via successive ionic layer absorption and reaction process (SILAR) and post-annealing in sulfur ambiance. The influence of the temperature of the heat treatment on the microstructure of the CuInS2 sensitized TiO2 electrodes and the photovoltaic performance of the solar cells were investigated. The crystallization degree of CuInS2 thin films increased with the increase of the heating temperature from 400 oC, 450 oC, 500 oC to 550 oC. With the increase of the heating temperature, the photoelectric conversion efficiency of the CuInS2 sensitized solar cells sharply increased from 0.13% (450 oC) to 0.84% (550 oC, Voc = 0.37 V, Jsc = 8.44 mA/cm2, FF = 0.27). This is attributed to the well crystallization of the CuInS2 nanoparticles and the decrease of the defects.

Abstract: The influences of ZnO photoanode structure on the properties of ZnO dye-sensitized solar cell were studied in this paper. Four kinds of ZnO photoanode films prepared from ZnO nanopowders, nanorods, nanosheets and aggregates were investigated. Their photovoltaic parameters were discussed and compared. ZnO cell consisted of ZnO aggregates had optimal properties, photoelectric conversion efficiency, open circuit voltage, short-circuit current and the fill factor of ZnO aggregates cells were 2.15%, 0.64V, 6.47mA•cm-2 and 0.52, respectively.

Abstract: For the first time, mesoporous ZnO and SnO₂ spherical particles were synthesized by spray reaction (SR) process. The synthesized materials were characterized by thermo-gravimetry/differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results reveal that few ZnO microspheres were formed after calcined at 700 °C while large quantity of non-spherical ZnO particles was produced. And the predominant hexagonal ZnO (h-ZnO) is attained when heated at 700 °C. Mesoporous SnO₂ microspheres prepared at 800 °C possess an average size ~2.22 μm and a major tetragonal phase (t- SnO₂) with crystallite size 7.8 nm.

Abstract: CuInGaSe2 (CIGS) is the family of semiconducting materials of the tetragonal chalcopyrite structure; it has emerged as a leading material for high efficiency and radiation-hard solar cell application. The CIGS powder was synthesized by a solvothermal method. The morphologies and microstructure of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and inductive coupled plasma (ICP). It was concluded that the powder has different component with the content of Ga in raw changed. SEM results showed that the size of 0.2 ~2m crystal was formed. ICP results indicated that the element molar ratio of Cu, In, Ga and Se is closer to the elements in raw materials when the reactive time is 48h. The electric properties of product have been investigated, and all the samples have small resistivity values.